“The September Issue,” a documentary about the creation of a single, very fat issue of American Vogue in a far-off gilded age (i.e., 2007), has little to say about fashion, the real ins and outs of publishing or the inner workings and demons of the magazine’s notoriously demanding meanie-in-chief, Anna Wintour. Rather, this entertaining, glib movie is about the maintenance of a brand that Ms. Wintour has brilliantly cultivated since she assumed her place at the top of the editorial masthead in 1988 and which the documentary’s director, R. J. Cutler, has helped polish with a take so flattering he might as well work there.

Anna Wintour, in her signature sunglasses, in a scene from 'The September Issue.' Next to her is Grace Coddington.

To judge from the flurries of behind-the-scenes evidence, however, if Mr. Cutler did work for the exacting Ms. Wintour he would still be doing reshoots. Shot on digital with an eye for sumptuous color by Bob Richman and briskly edited by Azin Samari, the 88-minute movie opens with Ms. Wintour explaining that “there is something about fashion that can make people very nervous.” Certainly she unnerves her staff, as you soon see from all the huddled bodies and popping eyes. Even the more self-possessed, like Candy Pratts Price, seem in the grip of awe. Is Ms. Wintour the “high priestess” of the magazine, an off-camera voice asks. “I would say pope,” Ms. Price says with a queasy smile.

Many will grasp this distinction, having already watched supplicants kiss the ring in the 2006 film “The Devil Wears Prada,” with Meryl Streep as a thinly disguised, fictionalized and Americanized version of Ms. Wintour. Etched in acid and often hilarious, the performance, while not wholly modeled on Ms. Wintour, helped humanize her public profile, lessening the sting of the original book, a roman à clef by one of her former assistants, Lauren Weisberger. The documentary continues this humanization largely by showing Ms. Wintour very hard at work, rather lonely and sensitive about her British family’s low opinion of fashion. She’s a poor little rich girl swaddled in fur and iced to the bone.

She’s also pretty funny, perhaps at times accidentally so. Much of the movie’s pleasure comes from the utter ease with which Ms. Wintour plays the Red Queen of fashion and orders off with their heads (and even tummies). In the case of the British actress Sienna Miller, the cover girl for the September 2007 issue, which gives the movie its structure and hook, the head in question receives the 21st-century version of a severing: it’s Photoshopped to unreal perfection. However lovely, Ms. Miller proves a problematic Vogue ideal for the editors, many of whose own faces are somewhat surprisingly scored with wrinkles. It’s a mark of how pitiless Ms. Wintour can come across that you end up feeling a bit sorry for Ms. Miller.

In truth Ms. Wintour was just doing her job. Yes, there’s cruelty here, but of the most attenuated kind: she says no, employees tremble. The strongest, like the flame-haired Grace Coddington, the magazine’s longtime creative director and the documentary’s hugely diverting stealth star, seem to have figured out how to survive with their dignity intact. Most of the truly ugly stuff in fashion — the models starving themselves, the exploited Chinese workers cranking out couture fakes and the animals inhumanely slaughtered for their fur — remains unnoted in “The September Issue,” much as it often does in Vogue. And while the movie shuns any overt discussion of money, it includes an instructive scene of Ms. Wintour playing the coquette with one of the magazine’s important advertisers.

Of course it really is all about money. Despite being crammed with glossy images of beautiful, weird, unattractive, ridiculous and prohibitively expensive clothes and accessories, Vogue isn’t about fashion: it’s about stoking the desire for those clothes and accessories. It’s about the creation of lust and the transformation of wants into needs. Almost everything in this temple of consumption, including its lavish layouts and the celebrities who now most often adorn its covers, hinges on stuff for sale. Some of that stuff comes with a price tag, but some of it is more ephemeral because Vogue is also in the aspiration business. Mr. Cutler doesn’t notice or doesn’t care about any of that, which makes his movie as facile as it is fun.

Given this, it’s no surprise that Ms. Wintour is doing her part to flog the documentary: she gave a party in its honor and recently appeared on David Letterman’s show, with and without her signature sunglasses, her glazed stare and tight smile firmly in place. The movie affords you many opportunities to marvel at the parsimony of that smile and wonder if she’s as bored as she looks, even while waiting for an agitated Stefano Pilati, the creative director at Yves Saint Laurent, to show his newest collection.

“That’s pretty,” she says, in a voice so drained of affect it’s a wonder he doesn’t commit seppuku with his scissors. You feel bad for Mr. Pilati, but it’s Ms. Wintour’s hauteur that makes you laugh and keeps you willingly at her side.